#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <math.h>
using namespace std;

int main() {
    string sa,sb,xa,xb,pa,pb;
    cin >> sa >> pa >> xa >> sb >> pb >> xb;
    if(pa.size() > pb.size())cout << sa << endl;
    else if(pa.size() < pb.size())cout << sb << endl;
    else if(pa > pb)cout << sa << endl;
    else if(pa < pb)cout << sb << endl;
    else cout << -1 << endl;
    return 0;
}